Generally there exists a variety of different stacked assemblies and structures in the context of electronics and electronic products.
The motivation behind the integration of electronics and related products may be as diverse as the related use contexts. Relatively often size savings, weight savings, material savings, cost savings, performance gain or just efficient cramming of components is sought for when the resulting solution ultimately reduces into a multilayer structure carrying electronics and exhibiting a desired shape. The associated use scenarios may be various and numerous, relating to e.g. product packages or food casings, visual design of device housings, wearable electronics, personal electronic devices, displays, detectors or sensors, vehicle interiors, antennae, labels, vehicle electronics, furniture, etc.
Electronics such as electronic components, ICs (integrated circuit), and conductors, may be generally provided onto a substrate element by a plurality of different techniques. For example, ready-made electronics such as various surface mount devices (SMD) may be mounted on a substrate surface that ultimately forms an inner or outer interface layer of a multilayer structure. Additionally, technologies falling under the term “printed electronics” may be applied to actually produce electronics directly and essentially additively to the associated substrate. The term “printed” refers in this context to various printing techniques capable of producing electronics/electrical elements from the printed matter, including but not limited to screen printing, flexography, and inkjet printing, through a substantially additive printing process. The used substrates may be flexible and printed materials organic, which is however, not always the case.
CAE (computer-aided design) generally refers to usage of computer software tools for engineering tasks. CAD (computer-aided design) and ECAD (electrical/electronic computer-aided design, or EDA electronic design automation), in turn, refer to usage of computers for overall design and specifically electronic system design, respectively.
Majority of contemporary computer-run tools for designing circuit layouts strongly rely upon planar, single layer or stacked, substrates such as ordinary glass epoxy based FR4 (flame retardant) type PCBs (printed circuit board) or flexible PCBs for hosting an electronics layer such as conductor traces and components, which induces many kinds of challenges in modern electrical and electronic design tasks due to a fact that while the integration level of electronics is on the rise as contemplated hereinbefore, more efficient integration cannot in the end solely rely upon simple planar shapes or specifically planar substrates, or single layer electronics, when the end products themselves are of various imaginative form and size.
The concept of injection molded structural electronics (IMSE) involves building functional devices and parts therefor, which encapsulate electronic functionality as seamlessly as possible. Characteristic to IMSE is also that the electronics is commonly manufactured into a true 3D (non-planar) form in accordance with the 3D models of the overall target product, part or generally design.
To achieve desired 3D layout of electronics on an 3D substrate and in the associated end product, the electronics may be still provided on an initially planar substrate, such as a film, using two-dimensional (2D) methods of electronics assembly, whereupon the substrate, already accommodating the electronics, may be formed into a desired three-dimensional, i.e. 3D, shape and subjected to overmolding, for example, by suitable plastic material that covers and embeds the underlying elements such as electronics, thus protecting and potentially hiding the underlying elements from the environment.
In the afore-explained context, traditional type of circuit layout design is particularly demanding as it is still essentially done in 2D domain using ordinary 2D ECAD tools while a designer has to keep in mind that the final product shape is substantially non-planar and may exhibit e.g. bent areas with modest or considerable curvature, different types of edges, cuts, etc. When an initially planar substrate is subjected to forming such as thermoforming, it, besides changing in shape, also locally deforms, basically elongates, through stretching together with an increase of a so-called draw ratio of the substrate, referring to the ratio of a surface area and footprint thereof.
One challenge arises from the correct positioning of circuit elements on the initial 2D surface from the standpoint of their intended target position in the formed 3D product. The target position of the circuitry in the 3D product may be based on different aesthetic and/or functional objectives associated with the circuitry, for example.
In addition, as the electrical properties of electronics and materials used therein, with reference to e.g. conductive traces and electronic components of potentially printed or mounted type, may change even radically when subjected to physical shear stress during and following a forming phase, it may easily appear that an originally electrically fully functional circuit design developed and perhaps simulated or tested using a 2D model or a 2D substrate, respectively, works sub-optimally or even fails miserably after 3D forming of a 2D preform carrying such design. It is indeed difficult to duly deduce upfront proper configuration of a variety of desired circuit features on a planar substrate having regard to both materials and locations thereof to ascertain their correct electrical operation also after 3D forming of the substrate, even if the positioning of at least portion of the circuit features in the final 3D shape is not originally, as such, an issue or in the particular interest of the designer.
Yet, various mountable ready-made electronics including e.g. dedicated components and integrated circuits (IC) may not withstand the necessary 3D-forming of the underlying substrate if positioned in locations subjected to high stress, with reference to e.g. ceramic or plastic packages thereof not forgetting the actual electrical or electronic features, and will break or at least detach from the substrate as a result.